Answer any of the following questions, please:
1) If the actinides beyond uranium were found in the earth's crust, and uranium's half-life is 4.5 billion years, would the half-lifes of the other elements be more or less?
2) Why do photographers work in low light when they work with materials containing selenium?
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2007-03-12 11:26:17 · 1 answers · asked by dreamer 2 in Science & Mathematics ➔ Chemistry
also... if the world were 80% oxygen and 20% nitrogen instead of the other way around, how would it be different?
2007-03-12 11:45:51 · update #1
a) Longer. The earth has been around for billions of years. If they had shorter lifetimes (like millions of years) they would have all decayed away by now. Plutonium, for example, may or may not have existed on earth, and it is certainly made in small quantities anywhere uranium exists. But it's lifetime is comparatively short (10,000s of years, compared to the age of the earth, which is billions of years) so it just decays away.
b) It's very photosensitive, and light can cause it to oxidize.
2007-03-12 11:38:19 · answer #1 · answered by Some Body 4 · 1⤊ 0⤋